As the skin ages, many people experience dissatisfaction in their appearance due to the development of lines and wrinkles in the skin, especially the face. Although the development of these lines and wrinkles is generally seen as a part of the natural aging process, for many individuals, the appearance of these lines and wrinkles is very traumatic and seriously affects their quality of life and their relationships with others. In addition, for a large number of people, the appearance of aging can affect their economic prospects. This is especially true for those seeking employment as actors or actresses or in other positions in the entertainment industry, but there is an increasing concern among an aging population that an aged appearance can affect their job prospects, even for jobs for which appearance is essentially unrelated to job performance.
Therefore, as a result of these concerns, there is a substantial need for products that can reverse some of the effects of the aging process and can act as dermal expanders and tissue fillers. Accordingly, a number of compositions are in use as dermal expanders and tissue fillers. Some of these are collagen-based. One alternative uses atelopeptide collagen alone, such as Zyderm (from bovine collagen), or micronized human collagen from cadavers. Another alternative uses cross-linked collagen, such as Zyplast, which uses bovine collagen cross-linked by glutaraldehyde, or Evolence, which uses porcine collagen cross-linked by ribose. Other compositions in use as dermal expanders and tissue fillers are hyaluronic acid-based, either native or cross-linked. These dermal expanders and tissue fillers have several problems. They have a great tendency to be resorbed, require repeated injections, and there is a risk of toxicity from the cross-linking agents used.
Another approach uses composites. These include, for example, CaHA microspheres suspended in a gel carrier (Radiesse), PMMA beads suspended in gelatin (ArteFill), PLA beads, TCP powder, or dextran beads in hyaluronic acid (HA). These composites also have several problems. For example, the beads used are non-biological and tend to migrate, which causes distortion of the appearance of the skin.
There are additional uses for dermal expanders and tissue fillers that require dermal expanders or skin fillers with improved properties. These are in breast augmentation, treatment for urinary incontinence, or treatment for esophageal reflux. Such dermal expanders and fillers can be employed in other surgical reconstructive processes. Such dermal expanders and fillers can also be employed in dental implants, where they can aid in bone regeneration.
Accordingly, there is a need for an improved dermal expander and tissue filler that is effective, safe, and whose effects are lasting. There is also a need for an improved dermal expander and tissue filler that can be employed in non-cosmetic applications such as breast augmentation, treatment for urinary incontinence, or treatment for esophageal reflux.